Vibro-gyratory mills

ABSTRACT

Vibro-gyratory mills for grinding or finishing purposes having a process chamber of annular shape in plan with a spiral floor and a separating chamber located beneath the upper end of the floor, there being a deflector member pivotally mounted at the region where the upper and lower ends of the floor meet, the deflector member being pivotally movable between a recirculating position in which it forms a chute extending between the upper and lower ends of the floor and a discharge position in which it forms a chute directing the charge from the upper end of the floor to said separating chamber.

United States Patent 1191 Fahey et al.

June 4, 1974 VIBRO-GYRATORY MILLS [75] Inventors: Dennis Fahey,

Newcastle-Under-Lyme; David Cunningham-Smith, Harpenden, both of England[73] Assignee: William Boulton Limited, Burslem,

Staffordshire, England [22] Filed: Oct. 5, 1972 [2]] Appl. No.: 295,388

[30] Foreign Application Priority Data Oct. 9. l97l Great Britain47097/71 [52] US. Cl 241/69, 241/78, 241/97 [5 l] Int. Cl. B02c 9/04[58] Field of Search 241/69, 70, 74, 78, 80, 241/8l,96, 97

[ 56] References Cited UNITED STATES PATENTS 3.703995 11/1972 Sullivanet al. 24'l/69 Primary ExaminerRoy Lake Assistant Examiner-DeWalden W.Jones Attorney, Agent, or Firm-Breitenfeld & Levine [57] ABSTRACTVibro-gyratory mills for grinding or finishing purposes having a processchamber of annular shape in plan with a spiral floor and a separatingchamber located beneath the upper end of the floor, there being adeflector member pivotally mounted at the region where the upper andlower ends of the floor meet, the deflector member being pivotallymovable between a recirculating position in which it forms a chuteextending between the upper and lower ends of the floor and a dischargeposition in which it forms a chute directing the charge from the upperend of the floor to said separating chamber.

9 Claims, 2 Drawing Figures VIBRO-GYRATORY MILLS The invention relatesto vibro-gyratory mills which may be used for grinding, polishing,de-burring or similar finishing operations and which effect suchoperations by means of a vibratory action in the form of a highfrequency rotary oscillation about a vertical axis with an upward anddownward component in the movement, such action being applied to acharge of workpieces or material, usually mixed with discrete finishingmedia, contained in the mill.

The term workpieces used hereinafter should be construed as referringnot only to components to be polished, de-burred or otherwise finishedbut also to materials which require to be ground or powdered.

The invention provides a vibro-gyratory mill having a processing ortreatment chamber which is of annular shape in plan and has an upwardslope in the floor, a vibratory mechanism serving to promote progressionof a charge of workpieces and media around said chamber, 21 separatingchamber including a horizontal separating screen at a level below thatof the upper end of the floor of the treatment chamber and having anoutlet through which, after screening, separated workpieces can bedischarged from the machine, means for returning the media to the lowerend of the floor of said treatment chamber, and a deflector memberpivotally movable between a recirculating position in which it forms achute extending between the upper and lower ends of the floor of thetreatment chamber, and a discharge position in which it forms a chutedirecting the charge from the upper end of said floor to said separatingscreen.

Preferably said deflector member is pivotally mounted between its endson an axis extending parallel to the upper edge of said floor anddisposed at a level between that of the upper end of the floor and saidseparating screen.

Preferably also the floor of said treatment chamber is of helical formwith a step connecting the upper and lower ends of the heliz, saidseparating chamber being disposed beneath the upper end of said helixwithin the confines of the annular treatment chamber. The separatingscreen is preferably disposed at or below the level of the lower end ofthe sloping floor of the treatment chamber.

An embodiment of the invention will now be described, by way of exampleonly, and partly with reference to the accompanying drawings, in which:

F l0. 1 is a fragmentary vertical cross-section through one form ofmachine according to the invention taken approximately on the line I-lin FIG. 2; and

FIG. 2 is a plan view of the machine shown in FIG. 1.

Referring to the drawings, there is shown the upper portion of avibratory mill comprising a generally cylindrical base portion on whichis supported, by a series of coil springs 11, a treatment chamber orbowl 12 of annularshape in plan. The major portion of the floor of thechamber is'of shallow helical form rising from a low level zone 13 to ahigh level zone 14. The floor of the chamber is of arcuate cross-sectionand the spaced, parallel walls of the chamber are provided with a rubberor other suitable lining.

The treatment chamber surrounds a central sleeve l6, also supported onthe springs 11, and within which a vibratory unit is located. Thiscomprises a motor 35 carried by upper and lower support rings 36 and 37and having a vertical shaft which projects from both ends of the motorcasing. Eccentric weights 38 and 39are carried by the respective ends ofthe motor shaft and are relatively angularly displaceable to control themotion imparted by the motor to the treatment chamber 12. By virtue ofthe provision of the eccentric weights and the resilient mounting of themotor and the treatment chamber on the springs, rotation of the motorimparts to the treatment chamber a high frequency rotary oscillationabout the central axis of the chamber having an upward and downwardcomponent in the movement. This movement causes a charge of workpiecesand media in the chamber to undergo generally orbital movement insubstantially vertical planes while moving up and around the chamberfrom the low level to the high level zones. During the movement themedia act upon the workpieces to effect a grinding, finishing or likeaction which can be varied depending on the speed of rotation and therelative angular displacements of the eccentric weights.

A short ramp 18 extends upwardly from the high level zone 14 at asteeper angle than the remainder of the chamber floor, and below thisramp is a separating chamber 24 housing a separating sieve or screen 25leading to a discharge opening 26 in the outer wall of the chamber. Adeflector plate or flow control gate 27 is pivotally mounted about atransverse horizontal axis 28 at a level between the upper end of theramp and the separating screen. This deflector plate may be moved by anysuitable manual or automatic means such as the knob 29 (FIG. 2) betweena discharge position shown in broken lines and a recirculating positionshown in full lines.

In the discharge position the charge falling from the upper end of theramp 18 is intercepted and directed down the plate 27 into the chamber24 and on to the screen 25, one component of the charge being retainedby the screen and delivered from the machine by way of the dischargeopening 26, and the other component falling through the screen into acollecting chamber 30 from whence it is returned to the main chamber 12by virtue of the vibratory movement imparted to the machine. Where,parts are being finished, the parts will generally be larger than themedia so that the parts will be discharged from the outlet 26 and themedia returned through the screen 25 and chamber 30 for reuse. in thecase of material which is being ground or powdered or where parts to befinished are smaller than the media, an additional collecting tray orthe like would berequired to receive the material passing through thescreen for delivery to a discharge outlet, the media falling from theend of the screen into the collecting chamber and returning from henceto the main chamber 12.

When the deflector plate 27 is in its recirculation position the chargeof workpieces and media slides down the deflector plate on to a floorplate 31 level with and forming part of the bottom of the main chamber12 to which the charge is thus returned for recirculation withoutseparating. This can be effected as often as desired and the movement ofthe deflector plate may be arranged to be effected automatically afterthe charge has been recirculated a desired number of times.

It should be noted that in this recirculation position the deflectorplate forms a chute extending between the upper and lower levels of thefloor of the main chamber 12. During recirculation the charge slidesdown this chute and does not fall directly from the top end to thebottom end of the floor. As a result of this feature the machine can beused for fine polishing since the surfaces of the parts are notscratched or otherwise damaged during recirculation.

The provision of the relatively gentle incline between the regions 13and 14 followed by the relatively steep incline of the ramp improvesprogression of the charge round the chamber compared with machineshaving a uniform spiral chamber floor. This is so because in climbingthe slope the workpieces, being generally heavier than the media, tendto slow down and thereby move closer together. Consequently to maintainadequate spacing of the workpieces after several circulations, theirinitial spacing when introduced must be increased and the throughput ofthe machine is thereby reduced. By virtue of the use of a long shallowincline followed by a short steep incline we have found that thisproblem is reduced and greater throughput can be attained.

A further advantage arises from the location of the separating screen ata low level beneath the upperend of the chamber floor. This provides acompact arrangement and renders the chamber accessible from abovethroughout its entire annular length. Separation takes place below thelevel of the lower end of the chamber floor and return of media to thechamber is effected by the vibratory movement which constrains the mediato travel up theinclined path connecting the collecting chamber 30 withthe low level end of the main chamber 12. It should also be noted thatthe charge is transferred to the separating zone using gravity.Previously proposed machines have utilised a high level separating zoneto which the charge must climb, and this arrangement imposesrestrictions on the extent to which the vibratory mechanism may beadjusted. By using gravity to transfer the charge for separating, therestrictions on the settings of the motor and weights are removed and awider range of vibratory movements can therefore be applied to theapparatus.

Various modifications may be made without departing from the inventionand it is envisaged that the chamber floor could be level for most ofits length and then provided with a steep ramp from which the charge mayeither fall back into the chamber or be deflected into the separatingchamber.

We claim:

1. A vibro-gyratory mill having a processing or treatment chamber whichis of annular shape in plan and has an upward slope in the floor, avibratory mechanism serving to promote progression of a charge ofworkpieces and media around said chamber, a separating chamber includinga horizontal separating screen at a level below that of the upper end ofthe floor of the treatment chamber and having an outlet through which,after screening, separated workpieces can be discharged from themachine, means for returning the media to the lower end of the floor ofsaid treatment chamber, and a deflector member pivotally movable betweena recirculating position in which it forms a chute extending between theupper and lower ends of the floor of the treatment chamber, and adischarge position in which it forms a chute directing the charge fromthe upper end of said floor to said separating screen.

2. A vibro-gyratory mill according to claim 1 wherein said deflectormember is pivotally mounted between its ends on an axis extendingparallel to the upper edge of said floor and disposed at a level betweenthat of the upper end of the floor and said separating screen.

3. A vibro-gyratory mill according to claim 2 wherein the floor of saidtreatment chamber is of helical form with a step connecting the upperand lower ends of the helix, said separating chamber being disposedbeneath the upper end of said helix within the confines of the annulartreatment chamber.

4. A vibro-gyratory mill according to claim 3 wherein said separatingscreen is disposed at or below the level of the lower end of the slopingfloor of said treatment chamber.

5. A vibro-gyratory mill according to claim 4 wherein said means forreturning the media to said treatment chamber comprises an upwardlysloping ramp having its lower end located beneath said separating screenand its upper end communicating with the lower end of the floor of saidtreatment chamber, the media discharged through the screen travelling upsaid ramp under the influence of the vibratory movement.

6. A vibro-gyratory mill according to claim 5 wherein the floor of saidtreatment chamber rises gently over most of its annular length andterminates in a relatively steep ramp portion.

7. A vibro-gyratory mill according to claim 5 wherein the floor of saidtreatment chamber is of arcuate crosssection and has upstanding sidewalls.

8. A vibro-gyratory mill according to claim 7 wherein said treatmentchamber is resiliently mounted on a fixed base by an annular series ofcoil springs.

9. A vibro-gyratory mill according to claim 8 wherein said vibratorymechanism comprises a motor carried by said chamber and having avertical shaft fitted with eccentric weights.

1. A vibro-gyratory mill having a processing or treatment chamber whichis of annular shape in plan and has an upward slope in the floor, avibratory mechanism serving to promote progression of a charge ofworkpieces and media around said chamber, a separating chamber includinga horizontal separating screen at a level below that of the upper end ofthe floor of the treatment chamber and having an outlet through which,after screening, separated workpieces can be discharged from themachine, means for returning the media to the lower end of the floor ofsaid treatment chamber, and a deflector member pivotally movable betweena recirculating position in which it forms a chute extending between theupper and lower ends of the floor of the treatment chamber, and adischarge position in which it forms a chute directing the charge fromthe upper end of said floor to said separating screen.
 2. Avibro-gyratory mill according to claim 1 wherein said deflector memberis pivotally mounted between its ends on an axis extending parallel tothe upper edge of said floor and disposed at a level between that of theupper end of the floor and said separating screen.
 3. A vibro-gyratorymill according to claim 2 wherein the floor of said treatment chamber isof helical form with a step connecting the upper and lower ends of thehelix, said separating chamber being disposed beneath the upper end ofsaid helix within the confines of the annular treatment chamber.
 4. Avibro-gyratory mill according to claim 3 wherein said separating screenis disposed at or below the level of the lower end of the sloping floorof said treatment chamber.
 5. A vibro-gyratory mill according to claim 4wherein said means for returning the media to said treatment chambercomprises an upwardly sloping ramp having its lower end located beneathsaid separating screen and its upper end communicating with the lowerend of the floor of said treatment chamber, the media discharged throughthe screen travelling up said ramp under the influence of the vibratorymovement.
 6. A vibro-gyratory mill according to claim 5 wherein thefloor of said treatment chamber rises gently over most of its annularlength and terminates in a relatively steep ramp portion.
 7. Avibro-gyratory mill according to claim 5 wherein the floor of saidtreatment chamber is of arcuate cross-section and has upstanding sidewalls.
 8. A vibro-gyratory mill according to claim 7 wherein saidtreatment chamber is resiliently mounted on a fixed base by an annularseries of coil springs.
 9. A vibro-gyratory mill according to claim 8wherein said vibratory mechanism comprises a motor carried by saidchamber and having a vertical shaft fitted with eccentric weights.